NOTNlCE
commented
2 years ago Power Management has always been tough on X99/C612. I suspect your CPU is not hitting full turbo frequency or proper stepping. There are only so many things we can do here, and I suspect the differences in your CPU score have to do with the frequency vectors being used and whether or not Speed Step was enabled in BIOS on your previous configuration.
In the previous EFI, your XCPM value is defined by SSDT - notably, SSDT-CP00-XCPM.aml. Without that definition, the system falls back to native frequency vectors in the iMacPro1,1 SMBIOS, which have some odd behaviors on our platform.
One thing you can test is re-injecting that SSDT from your old EFI. It should not cause a boot failure, as it is just XCPM data. I'd be very interested to see how it behaves on both your systems and if it requires any tweaks or breaks sleep. I'd also be very interested to see your frequency range with and without the SSDT. This can be monitored with Intel Power Gadget, but with laregely multi-core CPUs, the data gets a little jumbled because it averages all cores. In theory, these systems should be able to idle at 1.3~GHz (Minimum C-State on v3/v4 Xeons) and boost to the maximum turbo frequency of each CPU, but because of platform differences and non-native XCPM, the CPU does one of two things, depending on whether or not Speed Step is enabled. I suspect this toggle in BIOS is more likely the cause of your performance drop.
With Speed Step enabled, CPU idles properly, but doesn't boost properly. While I haven't seen this on my T5810 (mainly because I don't run it every day) I suspect a similar result as my main X99 system running on an ASUS motherboard. Even under load, the CPU frequency doesn't boost up which causes video playback stutter and other non-desirable behavior.
Which leads us to scenario #2, Speed Step disabled: With native frequency vectors (no external XCPM data) the CPU operates slightly above its base clock and stays relatively stable, regardless of load. No idle down frequency, and no boost to maximum turbo frequency.
Now, keep in mind, we are comparing different systems when I am talking about this CPU behavior, but I suspect similar results as the platforms are the same. As another test, I will take this XCPM SSDT and try it on my X99 tower to see how performance is impacted both with Speed Step enabled and disabled.
BillDH2k
Running stable under Catalina/Big Sur. But for some reason, the Geekbench 5 score is very low. The scores were only 733 (single-core), and 4967 (multi-core), with 2666V3 32GB RAM.
For comparison, the same hardware/OS install, running from my old OC setup (Catalina), the scores were much higher - 875, 7064, respectively. My speculation is that the CPU Power Management might not be running optimally. My old OC setup was from another GitHub contributor (link here).
By comparing the difference between the setup, an expert eye, like yours, might be able to fix this.
Thanks!